1002491 Fibre nib for Barigo Barograph approx 21mm long x 4mm sq protruding angled nib 5mm raised dovetail slot on back approx 8mm long x 2mm tapering to 1.5mm Fibre nib for Barigo Barographs, often will fit traditional barographs but there is no guarantee as pen arms vary in size. It is light weight and lasts quite a while (we have had customers report 4 years! but 2 or 3 perhaps more normal, depends on paper and environment where used) . Original Barigo stock ref F51077-06R-01 Most times the arm could be adapted to fit or carefully glued on if necessary. Size of pen is approx 21mm long by 4mm square with protruding angled fibre nib 5mm, the back has a raised dovetail slot approx 8mm long x 2mm tapering to 1.5mm. These are disposable and not intended for use with our ink. Minimum order value is £18 plus VAT - this item cannot be ordered individually - sorry.